Common Lochinvar Boiler Problems
Lochinvar builds reliable, high-efficiency boilers, but no gas appliance is immune to faults over a long BC heating season. Below are the problem areas we most commonly diagnose on Lochinvar Knight, WHN and SMART System series, what they tend to look like, and — importantly — why each one is work for a licensed gas technician rather than a DIY fix.
Most common Lochinvar fault areas
Lochinvar controls report faults across several systems. These are the categories we see most often, drawn from Lochinvar's own diagnostic codes:
- Ignition fault — typical signs: no heat or no hot water. Example Lochinvar codes: Ignition Failure.
- Flame failure — typical signs: boiler fires briefly then shuts down. Example Lochinvar codes: Flame Loss.
- Air-pressure / venting fault — typical signs: lockout, often worse in wind, rain or cold snaps. Example Lochinvar codes: Air Pressure Fault, Stack High Limit.
- Over-temperature / high-limit — typical signs: boiler locks out under load. Example Lochinvar codes: Outlet High Limit.
- Temperature-sensor fault — typical signs: erratic heating or hot-water temperature. Example Lochinvar codes: Inlet Sensor Fault, Outlet Sensor Fault.
- Water-flow / circulation fault — typical signs: no or weak heat. Example Lochinvar codes: Flow Switch Open.
- System water-pressure fault — typical signs: pressure gauge reading low (or very high). Example Lochinvar codes: Low Water.
- Combustion-fan fault — typical signs: no heat or hot water. Example Lochinvar codes: Blower Fault.
Symptoms you might notice first
- No heat — often ignition, flame-sensing, circulation or a sensor fault.
- No hot water (combi models) — frequently the plate heat exchanger, flow sensor or a DHW fault.
- Leaking or dropping pressure — a seal, the expansion tank, or the relief valve.
- Banging, gurgling or "kettling" noises — usually air or scale, sometimes circulation.
- Lockouts that return after a reset — a genuine fault the boiler is protecting against.
Why Lochinvar faults are not a DIY fix
Every one of these areas touches the sealed gas circuit, combustion, or safety controls. In British Columbia, diagnosing and repairing them legally requires a licensed gas fitter, and proper diagnosis needs combustion analysis and manometer gas-pressure testing. Repeatedly resetting a locked-out boiler can be dangerous — the fault code exists to protect you. The right move is to read the code, attempt at most one reset, and call a technician if it returns.
Lochinvar common problems — FAQ
What are the most common problems with Lochinvar boilers?
Across Greater Vancouver, the Lochinvar faults we see most are ignition and flame-sensing issues, air-pressure/venting faults (often worse in cold or windy weather), circulation and overheat lockouts, and pressure loss. The exact cause is confirmed with proper diagnosis, not guesswork.
Why does my Lochinvar boiler keep locking out?
A repeating lockout means the underlying condition — ignition, flame, venting, pressure or temperature — is still present. The reset clears the code but not the cause. If your Lochinvar boiler locks out again after one reset, switch it off and book a diagnosis.
Can I fix a Lochinvar fault code myself?
You can safely read the code and reset once. Beyond that, Lochinvar faults involve gas, combustion or safety systems that BC law reserves for licensed gas fitters — and DIY attempts can void your warranty and create a hazard.
Related Lochinvar resources
Common Problems for other boiler brands
Lochinvar boiler service near you
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- Lochinvar boiler service in New Westminster
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